[piaseczek]

Post a picture, I think yours was 74AC244D, lower current output version of the 74HC244D.
74ALVC has higher current output.

I think you should eliminate the software player as possible cause before modifying the hardware.

If you have the 74AC244, and want to use the 74ALVC244 the ceramic cap in the red squares have to be replaced with Polymer caps.
I use the 820uF Nichicon FP-RNL

Thank you, it looks like an another great mod as important as replacing the galvanic isolator.

What software player do you recommend?
I am using the Daphile with the RT kernel.

 

[b0bb]

Thank you, it looks like an another great mod as important as replacing the galvanic isolator.

What software player do you recommend?
I am using the Daphile with the RT kernel.

If you are looking for a better playback setup than Daphile, take a look at Roon or HQplayer.

The main playback/processing engine is separated from the audio endpoint.
It does not need to compete for resources with the playback engine
Audio endpoint is solely responsible for delivering data to the DAC, most importantly the buffering and flow control of that data.


Flow control when properly implemented, eliminates the audio dropout issues and popping noises.
This reduces jitter of the audio feed going into the DAC.

 

[piaseczek]

If you are looking for a better playback setup than Daphile, take a look at Roon or HQplayer.

The main playback/processing engine is separated from the audio endpoint.
It does not need to compete for resources with the playback engine
Audio endpoint is solely responsible for delivering data to the DAC, most importantly the buffering and flow control of that data.


Flow control when properly implemented, eliminates the audio dropout issues and popping noises.
This reduces jitter of the audio feed going into the DAC.

When using the USB input I don't have any problems with the dropouts, I am using the lowest DPLL setting.

Thank you, I will take a look at Roon.

My daphile (squeezelite) is configured similar to:
https://soundcheck-audio.blogspot.com/p/in-part-3-of-audio-engine-series-id.html

 

[ESL57]

What operating system software and player are you using to send DSD to the DAC?
004 is quite fussy about the quality of the DSD sent to it.

Have you tried HQPlayer ?
Time limited demo is free, available for Linux/Windows/Mac.

Try it with Amanero, no driver needed for Linux/MAC, ASIO driver needed for Windows.

Bobb that was my starting point, discarding that the source of the noises was the USB (Amanero with the power supply the same as yours) then Gustard u16 the same, or the playback software, I tried with HQplayer, Foobar2000, Vcl amp, etc, multiple changes of desktop pc, laptop (with battery only), windows 10, windows7 both 32 and 64 bit versions. Something I don't understand is that if the noises are occurring, if you turn off the LKS and turn it on again the sound clears for a few seconds (quite a few) and then they come back again.
Also remember that there were users This first version of LKS004 (17-04 firmware) that reported this same problem here, I think I remember someone from Australia, which makes me think that something was corrected in later versions. I also tried to turn on without connecting the connector of the front display / keyboard module, the dac continues to work anyway, it will keep the setting parameters the same, only that they cannot be seen or changed as is logical, this module is not the cause either. Another user would surely have thrown away this dac, for me it became a fun / entertainment and a challenge to be able to find the cause.

 

[b0bb]

Bobb that was my starting point, discarding that the source of the noises was the USB (Amanero with the power supply the same as yours) then Gustard u16 the same, or the playback software, I tried with HQplayer, Foobar2000, Vcl amp, etc, multiple changes of desktop pc, laptop (with battery only), windows 10, windows7 both 32 and 64 bit versions. Something I don't understand is that if the noises are occurring, if you turn off the LKS and turn it on again the sound clears for a few seconds (quite a few) and then they come back again.
Also remember that there were users This first version of LKS004 (17-04 firmware) that reported this same problem here, I think I remember someone from Australia, which makes me think that something was corrected in later versions. I also tried to turn on without connecting the connector of the front display / keyboard module, the dac continues to work anyway, it will keep the setting parameters the same, only that they cannot be seen or changed as is logical, this module is not the cause either. Another user would surely have thrown away this dac, for me it became a fun / entertainment and a challenge to be able to find the cause.

Have you tried to use a low DSD rate, if not lock it down to DSD64 and see what happens, check the display shows DSD64.
It is worth checking this again to confirm what DSD rate this problem is heard.

Measure the voltage output of the LT1763's supplying the 9038, nominal voltage output is 1.2V, nominal input voltage is 5V
Do this at cold start where you are not hearing the noise, repeat the measurement when you hear the noise.

Clean up the soldering mess, there is flux residue everywhere, especially around the I/V input and XO.

 

[ESL57]

Have you tried to use a low DSD rate, if not lock it down to DSD64 and see what happens, check the display shows DSD64.
It is worth checking this again to confirm what DSD rate this problem is heard.

Measure the voltage output of the LT1763's supplying the 9038, nominal voltage output is 1.2V, nominal input voltage is 5V
Do this at cold start where you are not hearing the noise, repeat the measurement when you hear the noise.

Clean up the soldering mess, there is flux residue everywhere, especially around the I/V input and XO.

Thanks Bobb, I already have new work to do on my diabolical toy, if I don't get it sometime, I'll finally have to call an exorcist, I still have psychophonies of some spirit inside (LOL).

 

[Xoverman]

Thanks Bobb, I already have new work to do on my diabolical toy, if I don't get it sometime, I'll finally have to call an exorcist, I still have psychophonies of some spirit inside (LOL).

If the noise is present on all 4 channels then the problem has to be in front of the DAC chips.
Digital signal chain, or as B0bb pointed out the PLL. Or noise on the clock power supply.

 

[piaseczek]

Yes.

In order to avoid cutting the PCB trace, the resistors require special placement.

Check with someone with the needed skills and a Gen2 like @Xoverman to help get the specific implementation steps worked out.
As I do not have a Gen2, someone needs to verify that the Gen2 boards do not have the mentioned resistor.

It is likely that Gen2 boards can only accommodate 1 resistor per channel vs 2 on the Gen1, this is not an issue

Xoverman,
Are you going to add the 22ohm resistor between the Vcom cap and the analog?
If yes please let us know how to do it in the Gen2 units

 

[ESL57]

If the noise is present on all 4 channels then the problem has to be in front of the DAC chips.
Digital signal chain, or as B0bb pointed out the PLL. Or noise on the clock power supply.

Yes,I think the solution has to be very close and in this area of the regulators close to 9038 and the clock, remember that I already changed all the lm317 for low noise modules, schottky diodes in all the rectification, I remember someone asking Jinbo about the need to update the firmware to the version of 18-08 and said that it was not necessary, I do not think this is but I am no longer certain of anything.

 

[Xoverman]

Xoverman,
Are you going to add the 22ohm resistor between the Vcom cap and the analog?
If yes please let us know how to do it in the Gen2 units

I'm really thinking about it.

@b0bb. Can you please post a picture of the position of all 4 resistors. In close up.

 

[b0bb]

I'm really thinking about it.

@b0bb. Can you please post a picture of the position of all 4 resistors. In close up.

 

[piaseczek]

b0bb,
when you replaced the FPCAPs around the es9038 to larger ones, did you remove the mkp/mkt bypasses?

 

[b0bb]

... did you remove the mkp/mkt bypasses?

No.
Is there a reason why you think it needs to be removed ?

 

[piaseczek]

No.
Is there a reason why you think it needs to be removed ?

I don't know whether it should be removed or not, I am not an expert like you.
Bypassing is a bit controvercial:
https://www.diyaudio.com/forums/power-supplies/307187-bypass-capacitor-theory-post5115988.html

 

[b0bb]

I don't know whether it should be removed or not, I am not an expert like you.
Bypassing is a bit controvercial:
https://www.diyaudio.com/forums/power-supplies/307187-bypass-capacitor-theory-post5115988.html

The approach LKS took with decoupling is correct, I am leaving things as-is.

Those kinds of discussions are all too common on diyaudio.
If you have the expertise and equipment to validate which of the competing claims are actually true , give it a try.